1. Field of the Invention
The present invention relates to a cantilever for use in an atomic force microscope (to be abbreviated to an "AFM" hereinafter) and a manufacturing method therefor, and, more particularly, to a cantilever using a diamond stylus.
2. Description of the Related Art
Hitherto, as a cantilever for an AFM using a diamond stylus, cantilevers have been disclosed in the following documents:
(1) U.S. Pat. No. 4,724,318, PA0 (2) G. Binnig, C. F. Quate and Ch. Gerber; Phys. Rev. Lett., Vol. 56, No.9, pp.930-933 (1986), PA0 (3) T. R. Albrecht and C. F. Quate; J. Vac. Sci. Technol. A, Vol.6, No.2, pp.271-274 (1988), PA0 (4) O. Marti, B. Drake and P. K. Hansma; Appl. Phys. Lett., Vol.51, No.7, pp.484-486 (1987), PA0 (5) O. Marti, B. Drake, S. Gould and P. K. Hansma; J. Vac. Sci. Technol. A, Vol.6, No.2, pp.287-290 (1988), PA0 (6) S. Alexander, L. Hellemans, O. Marti, J. Schneir, V. Elings, P. K. Hansma, Matt Longmire and John Gurley; J. Appl. Phys., Vol.65, No.1, pp.164-167 (1989)
Cantilevers of the type described above are respectively shown in FIGS. 7 to 9.
A cantilever 100A shown in FIG. 7 is arranged in such a manner that a diamond stylus 110A is secured to an end portion of a lever 120A by an adhesive so that the lever 120A is deflected by a degree corresponding to the atomic force acting between the diamond stylus 110A and a sample (omitted from the illustration). A cantilever 100B shown in FIG. 8 is arranged in such a manner that a diamond stylus 110B is secured to an end portion of a lever 120B, while another end portion of the lever 120B is supported by a supporting portion 140B. A cantilever 100C shown in FIG. 9 is arranged in such a manner that a mirror 150C is fastened to a lever 120C which holds a diamond stylus 110C whereby the deflection of the lever 120C due to the atomic force can be detected by an optical lever.
Since diamond is the hardest material having a Knoop hardness of 5700 to 10400 kgf/mm.sup.2 in the (100) plane, its point cannot be easily damaged even if it comes in contact with a sample or the like. Therefore, diamond is the most preferred material for the stylus.
Since each of the above-described cantilevers for use in the AFM must have a characteristic frequency higher than 100 Hz to detect an atomic force of 10.sup.-8 N or lower, its mass must be reduced. For example, in a case where the lever 120A shown in FIG. 7 is made of gold foil, the size of the cantilever 100A necessarily becomes reduced such that the lever 120A is about 25 .mu.m in thickness, 800 .mu.m in length and 250 .mu.m in width and the diamond stylus 110A is a pyramid-like stylus having a side of 100 to 200 .mu.m. As a result, a problem arises in that it is very difficult to handle the lever and the diamond stylus at the time of manufacturing the cantilever.
Another problem takes place in that the diamond stylus will deviate from a desired position or incline from a predetermined angle while the adhesive, which is used to secure the diamond stylus to the lever, is solidified. Therefore, the quality and the reliability of the cantilever may become unstable, and what is even worse, the manufacturing yield of the cantilever cannot be made satisfactory.